At work yesterday, a guy I am working with mentioned that one of the Sparkys in the company is currently inroled in some type of trade schooling. The guy said it was College class for Electrical Engineering, but the descriptions sound more like an NEC code class. That's not relavent, but felt that everyone should know [ joke].

Anyhow, he mentioned two conflicting things:

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[*]Pre-Twisting conductors prior to landing a Wirenut is not allowed anymore, due to the increased Resistance, therefore is non-compliant [I know what your thinking, I had the same reaction of ???] and

[*]Taping the sides of Receptacles is non-compliant [got me what this is about ]</OL>

Is there any validity to these claims per any code or Electrical Engineering studies currently taught???

I'll post this topic in the Holt forum and the IAEI forum [it's been over a year since I have even browsed the IAEI forum! hope I can still get a post in].

Anyone heard of this, or is this just a case of mistaken information [my first and last guess]?

The "no pre-twisting" may come from the statement on some wire nut containers that says "pre-twisting not required". It doesn't say that you can't pre-twist them. I can't think of any reason for the no tape rule. With solid wire, I always pre-twist the wires with my Kliens, and if the box is especially tight I have been known to tape up switches and receptacles, of course that was when we could work things hot.Don(resqcapt19)

Don is giving away his age(& probably mine) with his comment about taping & working hot.

I'd sure like to see the code citation about not taping receptacles.

As far as twisting is concerned, Don is correct. After all, Buchannon supplies a wire nut driver that is just about gauranteed to twist the wires unless you crank down the clutch on your cordless drill to a very low setting.

Tom

[This message has been edited by Tom (edited 12-27-2001).]

Few things are harder to put up with than the annoyance of a good example.

66. An area inspector has turned down installations because the electrician had not twisted the wires before installing spring connectors (wirenuts). Is this a valid position?

No. Section 110-3(b). They are not pre-twisted during UL tests. In fact, pre-twisting can possibly alter the "torquing effect" of the connector’s design. (Incidentally pre-twisting negates the benefit of these connectors. They do not have to be pre-twisted as you would for wrapping with electrical tape.)

Installation Instructions usually found on the smallest unit container (or inside bag) do not state to pre-twist the connectors.

I mentioned that the Manufacturers do not specify the conductors must be pretwisted, so that would rule out anything on that side [such as the turned down inspection for not twisting the wires].

It's obvious to me that UL would not pretwist, so that gives the Manufacturers "No need to pretwist" angle more validity.

Now, seeing people in the trade use the wirenut twister bit [for cordless drills], or the hand crank twisters - which are produced by the same Manufacturers which make the wirenuts being installed - I wonder if this is acceptable?

Like everyone else, I have been pretwisting conductors [with Linemans' pliers AKA "Kliens"], trim them as needed, then land the wirenut firmly enough to hold as an Insulator to the splice - rather than the sole conductor. This equals out to a tightness which does not distort the wirenut, nor pulls apart from the "Tug Test".

I'll have to print this thread out and present it.

It will be almost impossible to not pretwist after doing so for 18+ years!!!

Now as to the taping of Receptacles thingee, that one just sounds weird!I would like to see a design or safety issue concerning this!

I could not find anything in the UL white book that prohibits pre-twisting. I always used my long nose pliers, and lineman pliers and twisted the wires before using awirenut.

The use of tape at receptacle, or other device or equipment termination screws is just some additional insurance that one will not get a shock when replacing receptacles, because they forgot to turn off the power!

I was taught by my dad early on to use tape and I still use tape to protect myself!

Like most anything else, the pre-twisting can be done incorrectly.I've run across a high number of failed connections where the wires were pre-twisted to the point that the diameter of the twisted conductors was large enough that the wirenut couldn't get any purchase on the connection. The wire nut in this case serves no more purpose than that of a piece of tape. Very often the wirenut has fallen off as soon as I touched it.Also, I've found connections where 1 or more of the conductors has slid back from the rest when twisted and makes poor contact or none at all.I've never been a "pre-twister", and only know of a couple of connections I've ever had fail.(in 30+ yrs)My big gripe is with the use of wirenuts out of their listed range. It seems like some people think that they only come in one size...Red. Anything from 2-#18 to 7 or 8-#12 get stuffed in them. (The yahoos that overfill them often wrap them with tape to keep them from falling off). This has been the singlemost often cause of failures I've run into personally, and most commonly have been on neutrals because more of them are tied together in a box on multiwire circuits. (Naturally, because this is the most destructive connection to lose!)

I have looked at the instructions for wirenuts from: 3M, Buchanan, Gardner-Bender, Thomas & Betts, and Ideal. All of the instructions allow for pre-twisting or no pre-twisting, it appears to be the installer's choice.

The problem with pre-twisting is not the final twist of the conductors. There are two areas of concern, first damage to the conductors done by the jaws of the tool. Second, the loss of contact between some conductors and the spring of the wire nut (for example a #18 ballast lead may be hidden in the twist creases of (2) #12).